Wedge anchor for tensioning and anchoring wires



March 10, 1964 BODUROFF ETAL 3,123,879

WEDGE ANCHOR FOR TENSIONING AND ANCHORING WIRES Filed Jan. 18. 1960 2Sheets-Sheet l Lu/fcho Boduroff Homayoun J. Meheen March 10, 1964BODUROFF ETAL 3,123,879

WEDGE ANCHOR FOR TENSIONING AND ANCHORING WIRES Filed Jan. 18, 1960 2Sheets-Sheet 2 Fig. 5

f I l4 "li Lu/lcho Boduroff Homayoun J. Meheen ZNVENTORS i BY @waafiumin away 3m United States Patent 3,123,879 WEDGE ANQHUR FGE! TENQQNEQGAND ANCHDRIYG WIRES Lultcho Bodurolf, Denver, and Homayoun J. Meheen,

Cherry Hills Village, Enid, assignors to ll d: M

Frestress Corp, Englewood, Colo.

Filed .lan. l8, 1%9, Ser. No. 2,53% 19 Claims. (Cl. 24-122.6)

This invention comprises a novel and useful wedge anchor for tensioningand anchoring wires and more particularly relates to a means for posttensioning structures, and especially those of a concrete nature.

The principal object of this invention is to provide a means wherebyprestressing wires may be effectively post tensioned and securelyanchored under tension in a building structure.

A further object of the invention is to provide a means whereby aplurality of prestressing wires may be securely anchored and posttensioned in concrete members.

A further object of the invention is to provide a small compactanchoring means whereby a plurality of prestressing wires may be posttensioned and anchored as prestressing for various structural elements.

A still further object of the invention is to provide a means whereby aplurality of prestressing wires disposed in side-by-side arrangement maybe securely anchored and post tensioned in building structures andwherein the loads applied to the prestressing wires will be effectivelydistributed between the same.

Yet another object of the invention is to provide a prestressing wireand anchor construction whereby a single anchor fitting and its lockingmeans shall be effective for effectively anchoring and securing undertension at plurality of prestressing wires in which the number of wiresis subject to variation and the arrangement of the wires is likewisevariable.

A. further and specific object of the invention is to provide ananchoring means for the post tensioning of prestressing wires whichshall effect an improved gripping action upon the wires, will maintainthe wires in a spaced relation with respect to each other, and will havea positive gripping and non-slipping action upon the wires.

Still another object of the invention is to provide an apparatus wherebya plurality of prestressing wires may be selectively post tensioned andthen securely anchored.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURES 1-7 relate to a preferred form of anchoring means for posttensioned prestressing wires and in which:

FIGURE 1 is a perspective view, partly broken away and shown in sectionof the anchoring means by which a plurality of prestressing wires areanchored under tension in accordance with the invention;

FIGURES 2 and 3 are perspective views of one of the anchoring wedgesemployed in the arrangement of FIG- URE 1;

FIGURE 4 is an end elevational view taken from the left end of FIGURE 1but with the prestressing wires omitted therefrom;

FIGURE 5 is an end elevational view taken from the right end of FIGURE 1but with the prestressing wires omitted therefrom;

FIGURE 6 is a vertical longitudinal sectional view through the anchoringmeans of FIGURE 1 being taken substantially upon the plane indicated bythe broken section line 6-6 of FIGURE 5; and

3,123,879 Patented Mar. 16, 1964 FIGURE 7 is a vertical transversesectional detail view taken substantially upon the plane indicated bythe section line 77 of FEGURE 6.

Referring now to the embodiment of FIGURES 1-7 which constitutes apreferred embodiment in accordance with the principles of thisinvention, it will be observed that the numeral 1t} designates generallythe anchor by which a plurality of prestressing rods or similar elements12 are locked in position and under tension through the agency of aplurality of locking wedges each designated generally by the numeral 14.

The anchor ill comprises a metallic cylindrical body it having alaterally projecting anchoring flange 18 at one end thereof. The body isprovided with a conical locking surface 2% extending axiallytherethrough, the larger end of this bore 2t} emerging upon the surfaceof the anchoring flange 18, while the smaller end of the bore opens atthe other end of the body. The bore is preferably circular incross-section and there are provided a series of complementary lockingwedges 14, six being considered quite satisfactory for the purposes ofthis invention. These locking wedges are of a particular constructionfor the purpose of this invention.

Referring now especially to FIGURES 2 and 3 it will be observed thateach of the locking wedges 14 has a convex outer surface 2?. which iscomplementary to the conical locking surface of the bore 26' of the body16 together with a pair of planar radially extending side surfaces, eachdesignated by the numeral 2d while the smaller inner edge of the wedge14 has a flat surface 26.

Upon each of the two side faces there is provided a semi-cylindricalchannel or groove as at 23 which, as shown in FIGURES l, 6 and 7 areadapted to receive the prestressing wires or elements 12 therebetween.The depth or" these channels are slightly less than the radius of theprestressinig Wires or elements 12 in order that when the wires aredisposed in the complementary grooves or channels of the adjacent planarfaces 24 of adjacent wedges, and the wedges forced radially inward oragainst each other, the faces 24 of adjacent wedges will be slightlyspaced to thereby cause the surfaces of the registering complementarychannels of adjacent wedges to tightly frictionally grip and lock theprestressing wires or elements 12. therebetween. At the same time, thereis provided a central space through the series of wedges and extendingaxially of the bore 2d which provides a clearance to permit radialmovement of the wedges in the bore as the wedges, when shiftedlongitudinally of the bore are forced toward each other.

The outer convex face 22 of each wedge has a longitudinally extendingmedial groove or channel 2% of a depth slightly less than the diameterof a wire or rod 12 for receiving the latter and wedging it tightlyagainst the surface of the bore 24} when the wedges are driven intoplace.

Preferably the thicker or outer ends of the locking wedges 14 have fiatsurfaces 36 while similar surfaces 32 may be provided upon the inneredges of these wedges. The outer surfaces are employed to receive thepressure of a suitable tool, such as that shown in FIGURES 1621 anddescribed hereinafter, whereby the wedges will be forced inwardly of thebore 20 and into locking engagement with the prestressing wires orelements.

The anchor ll) is specifically adapted for disposition in a recess orsocket in the end of a concrete member or other structural element, itbeing understood that a' suitable oore extends through the beam orelement for the reception of the tensioning members 12. However, theprecise manner in which the anchor Ill and its anchoring flange 13 issecured to the structural member for which the reinforcements 12 areintended, is in itself not critical for the purpose of this invention.

21) of the anchor, and suitably post tensioned, with the locking wedges14 being loosely received in the bore 2%) and seating the prestressingwires 12 therebetween, the locking wedges 14- are driven into the bore29 until the conical bore forces the wedges circumferentially towardeach other and radially towards the bore and thereby causes the wedgesto frictionally grip and return the ten- 1 sioned elements 12. When thiscondition occurs, it is obvious that in view of the extensive surface tosurface contact with the prestressing elements with the wedges, and ofthe wedges with the bore 20, and when the tensioning means is disengagedfrom the prestressing wires 12, that the latter will in turn have theirtension imparted to the wedges. Thus a self-locking structure isprovided, inasmuch as any extra or additional pull from one of the wireswill result in further increasing the locking action of the entireassemblage.

In the arrangement illustrated in FIGURES l7 the locking wedges canreceive, retain and anchor a maximum of twelve or more of the wires orelements 12. However, it is evident that the same construction cansatisfactorily lock in post tensioned position any number of wires fromtwo to ten inclusive or twelve wires by appropriately distributing theprestressing wires between the six sets of locking channels of thewedges and between the two concentric rows of radially spaced lockingchannels. The two sets of channels 28 and 2% are radially spaced andstaggered circumferentially of each other to effect a uniformdistribution and spaces of the elements 12 from each other.

It is further evident that more than six radially locking channels maybe used to anchor a greater number of prestressing elements than thetwelve shown in FIGURES 1-7.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. An anchor for tensioned prestressing elements comprising an elongatedbody having an opening extending entirely therethrough, said openinghaving a central longitudinal axis with the wall of said opening beingtapered from end to end, a plurality of prestressing elements eachhaving a straight and nontwisted portion, said portions being disposedwithin said opening in circumferentially spaced side-by-side relationabout said axis, a plurality of wedges disposed in said opening incircumferentially' spaced side-by-side relation about said axis and eachdisposed between a pair of adjacent element portions, adjacent surfacesof adjacent wedges having registering pairs of complementary rectilinearchannels, each pair of registering channels being of sufficientcross-sectional area to receive and to compressively grip and retaintherein the straight portion of a single prestressing element in a twistfree condition, said channels being spaced from said opening wall, saidwedges having other surfaces cooperating with said opening wall forsqueezing said wedges and their associated registering channels towardseach other when the wedges are forced axially of said body opening.

2..The combination of claim 1 wherein said channels are of uniformcross-sectional area and shape throughout their length and are smoothand free of projections upon their complementary registering surfaces.

3. The combination of claim 1 wherein said body opening wall isfrusto-conical. V

4. The combination of claim 1 wherein the longitudinal axes of saidregistering channels are mutually divergent from the smaller diameter tothe larger diameter of said body opening.

5. The combination of claim 1 wherein the longitudinal axes of saidregistering channels are spaced uniformly from each other and areequidistant from said central longitudinal axis.

6. The combination of claim 1 wherein the longitudinal axes of saidregistering channels are disposed in opposed pairs on opposite sides ofsaid central longitudinal axis and are spaced from each other and areequidistant from the wall of said opening.

7. The combination of claim 1 wherein said elements are disposed inbalanced relation about said central longitudinal axis wherein theirtensions will be balanced about the latter.

8. The combination of claim 1 wherein said wedges have a lengthsubstantially equal to that of said opening.

9. The combination of claim 1 wherein said wedges are of such length asto engage said opening wall over substantially the entire length of thelatter.

10. The combination of claim 1' wherein said wedges are cut away alongone surface thereof to provide a clearance between said wedges and thesaid central longitudinal axis.

11. The combination of claim 1 wherein said wedges are generally arcuatein transverse section and have outer arcuate faces cooperatinglyengaging said opening wall.

12. The combination of claim 1 wherein said wedges are disposed in setsof circumferentially spaced wedges, each set having its wedges sopositioned about said central longitudinal axis as to produce a balancedtension about the latter.

13. The combination of claim 1 wherein said wedges include outer faceswhich are transversely arcuate and have a cooperating wedging andsliding engagement with said opening wall, said outer faces having eacha straight,

longitudinally extending recess therein, one of said element portionsbeing received in each of said recesses and compressively clampedtherein between said recessand opening wall.

14. The combination of claim 1 wherein said wedges include outer faceswhich are transversely arcuate and have a cooperating wedging'andsliding engagement with said opening wall, said outer faces having eacha straight, longitudinally extending recess therein, one of said elementportions being received in each of said recesses and compressivelyclamped therein between said recess and opening wall, said recessesbeing circumferentially spaced from said registering channels.

15. The combination of claim 1 wherein each wedge has a transverselyarcuate outer face cooperatingly and wedgingly engaging said openingwall and a planar inner face spaced from'said central longitudinal axistogether with a'pair of planar side faces, said side faces having saidregistering channels therein.

16. The combination of claim 1 wherein each wedge has a transverselyarcuate outer face cooperatingly and wedgingly engaging said openingwall and a planar inner face spaced from said central longitudinal axistogether with a pair of planar side faces, said side faces having saidregistering channels therein; each of said faces extending the length ofsaid opening and said outer faces having continuous engagement with theopening wall throughout the length of the latter.

17. The combination of claim 1 wherein each wedge has a transverselyarcuate outer face cooperatingly and wedgingly engaging said openingWall and a planar inner face spaced from said central longitudinal axistogether with a pair of planar side faces, said side faces having saidregistering'channels therein, each of said outer faces having alongitudinally extending, straight medially disposed recess therein,each recess receiving and compressively reamaeve taining one of saidelement portions therein and against said opening wall.

18. The combination of claim 1 wherein said body is provided With anexternally projecting mounting flange, the outer surface of saidmounting flange and the adjacent end of said body being coplanar wherebythe inner surface of said mounting flange Will be abutted against theouter surface of an article When said body is completely embedded in thelatter.

19. The combination of claim 1 wherein said body is provided with anintegral externally projecting mounting flange at one end and completelysurrounding said body, said opening in said body being convergentlytapering from said mounting flange to the other end of said body wherebysaid mounting flange may be engaged with the outer surface of an objectin Which said elements are dis- P 0 posed when said body is completelyembedded in said object.

References Cited in the file of this patent UNITED STATES PATENTS1,606,789 Hooley Q Nov. 16, 1926 2,177,364 Fotsch Oct. 24, 19392,458,304 Runde Jan. 4, 1949 2,641,810 Gasink June 16, 1953 2,763,464Leonhardt Sept. 18, 1956 2,834,081 Stump May 13, 1958 2,844,356Siegfried July 22, 1958 2,856,662 Clark et al. Oct. 21, 1958 FOREIGNPATENTS 165,577 Austria Mar. 25, 1950 225,354 Australia Nov. 11, 1959

1. AN ANCHOR FOR TENSIONED PRESTRESSING ELEMENTS COMPRISING AN ELONGATEDBODY HAVING AN OPENING EXTENDING ENTIRELY THERETHROUGH, SAID OPENINGHAVING A CENTRAL LONGITUDINAL AXIS WITH THE WALL OF SAID OPENING BEINGTAPERED FROM END TO END, A PLURALITY OF PRESTRESSING ELEMENTS EACHHAVING A STRAIGHT AND NONTWISTED PORTION, SAID PORTIONS BEING DISPOSEDWITHIN SAID OPENING IN CIRCUMFERENTIALLY SPACED SIDE-BY-SIDE RELATIONABOUT SAID AXIS AND EACH DISPOSED BETWEEN A PAIR OF ADJACENT ELEMENTPORTIONS, ADJACENT SURFACES OF ADJACENT WEDGES HAVING REGISTERING PAIRSOF COMPLEMENTARY RECTILINEAR CHANNELS, EACH PAIR OF REGISTERING CHANNELSBEING OF SUFFICIENT CROSS-SECTIONAL AREA TO RECEIVE AND TO COMPRESSIVELYGRIP AND RETAIN THEREIN THE STRAIGHT PORTION OF A SINGLE PRESTRESSINGELEMENT IN A TWIST FREE CONDITION, SAID CHANNELS BEING SPACED FROM SAIDOPENING WALL, SAID WEDGES HAVING OTHER SURFACES COOPERATING WITH SAIDOPENING WALL FOR SQUEEZING SAID WEDGES AND THEIR ASSOCIATED REGISTERINGCHANNELS TOWARDS EACH OTHER WHEN THE WEDGES ARE FORCED AXIALLY OF SAIDBODY OPENING.